X-ray

noun

1.

electromagnetic radiation emitted when matter is bombarded with fast electrons. X-rays have wavelengths shorter than that of ultraviolet radiation, that is less than about 1 × 10–8 metres. They extend to indefinitely short wavelengths, but below about 1 × 10–11 metres they are often called gamma radiation

(as modifier): X-ray astronomy

2.

a picture produced by exposing photographic film to X-rays: used in medicine as a diagnostic aid as parts of the body, such as bones, absorb X-rays and so appear as opaque areas on the picture

A high-energy stream of electromagnetic radiation having a frequency higher than that of ultraviolet light but less than that of a gamma ray (in the range of approximately 1016 to 1019 hertz). X-rays are absorbed by many forms of matter, including body tissues, and are used in medicine and industry to produce images of internal structures. See more at electromagnetic spectrum.

An image of an internal structure, such as a body part, taken with x-rays.

x-ray definition

Note: Because x-rays can travel through solid material and affect photographic plates, they are widely used in diagnosing medical problems.

Note: Objects in the sky also send out x-rays in processes that use very high energy.

x-ray definition

A photograph or image obtained through the use of x-rays. An x-ray is taken when an image of internal body structures (such as bones or organs) is needed to diagnose disease or determine the extent of injuries.